This project is not actively maintained, so I can take a time for responding the issues.
Jul-2020: Soon I'll update the wiki and send some updates.
This is a gui tool for testing ISO8583 protocol (requests and responses), and a java library as well. Through this tool you can:
The messages can be at many encoding formats, inclusive mainframe EBCDIC.
It is under development (not released yet), so you may find some UI bugs.